Python: Push an item on the heap, then pop and return the smallest item from the heap

Last update on April 01 2025 13:21:27 (UTC/GMT +8 hours)

23. Heappushpop Operation

Write a Python program to push an item on the heap, then pop and return the smallest item from the heap.

Sample Solution:

Python Code:

import heapq
heap = []
heapq.heappush(heap, ('V', 3))
heapq.heappush(heap, ('V', 2))
heapq.heappush(heap, ('V', 1))
print("Items in the heap:")
for a in heap:
	print(a)
print("----------------------")
print("Using heappushpop push item on the heap and return the smallest item.")
heapq.heappushpop(heap, ('V', 6))
for a in heap:
	print(a)

Sample Output:

Items in the heap:
('V', 1)
('V', 3)
('V', 2)
----------------------
Using heappushpop push item on the heap and return the smallest item.
('V', 2)
('V', 3)
('V', 6)

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to push an item onto a heap and then immediately pop the smallest item using heapq.heappushpop, printing both results.
• Write a Python script to demonstrate the heappushpop function by inserting an element and then returning the minimum element, showing the heap before and after.
• Write a Python program to add an item to an existing heap using heappushpop and then print the smallest element returned and the modified heap.
• Write a Python function to perform heappushpop on a heap and then verify the returned value is indeed the smallest among the original items.

Python Code Editor:

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Next: Write a Python program to create a heapsort, pushing all values onto a heap and then popping off the smallest values one at a time.